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A method for reducing cracking of dry-pressed strontium ferrite outer radial multi-pole magnetic ring

A technology of strontium ferrite and multi-pole magnetic rings, which is applied in the field of reducing the cracking of strontium ferrite external radial multi-pole magnetic rings by dry pressing, and can solve the problems of increasing unsafe factors in the production process, magnetic flux leakage in the splicing gap, and increasing production costs and other problems, to achieve the effect of reducing the radial uneven shrinkage trend, no cracking problem, and improving product yield

Active Publication Date: 2021-10-26
HUNAN AEROSPACE MAGNET & MAGNETO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Conventional permanent magnet rotors are spliced ​​by multiple pieces of magnetic tiles, which usually have the following disadvantages: 1) Difficulty in assembly; 2) Flux leakage in the splicing gap; 3) Non-sinusoidal distribution of surface magnetic flux, which makes the motor have obvious torque ripple and Cogging effect, high energy consumption and high noise
Therefore, this mold structure causes frequent damage to the upper and lower molds and cavity liners, which greatly increases production costs, reduces production efficiency, and increases unsafe factors in the production process

Method used

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  • A method for reducing cracking of dry-pressed strontium ferrite outer radial multi-pole magnetic ring
  • A method for reducing cracking of dry-pressed strontium ferrite outer radial multi-pole magnetic ring
  • A method for reducing cracking of dry-pressed strontium ferrite outer radial multi-pole magnetic ring

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] (1) Take 100 kg of Y35 strontium ferrite dry-pressed powder, add 1 kg of camphor powder and 1 kg of calcium stearate, stir and mix at 800 r / min for 180 min, then pass 60 Mesh sieve to get mixed powder;

[0032] (2) Fill the mixed powder obtained in step (1) into the mold, and then press it into a ring green body. The structure of the mold is as follows: Figure 1-3 As shown; during molding, by applying a radial 4-pole magnetic field on the outer edge of the middle mold, the green body has an outer radial 4-pole orientation, the molding pressure is 25 MPa, the forming magnetic field strength is 5000 Oe, and the obtained green body has a density of 2.8 g / cm 3 ;

[0033] (3) Place the obtained body in an electric kiln, heat up to 1200°C at a rate of 3°C / min, sinter for 1.5 h, and grind;

[0034] (4) Magnetize and inspect the ground product.

[0035]The results show that the average value of the peak value of the surface magnetic flux density of the obtained ferrite ext...

Embodiment 2

[0037] (1) Take 100 kg of Y45 strontium ferrite dry-pressed powder, add 1 kg of camphor powder, 0.5 kg of stearic acid amide (-325 mesh) and 0.5 kg of oleic acid amide (-325 mesh), and stir Mixing, the rotating speed is 29000 r / min, the time is 5min, then pass through a 40 mesh sieve to get the mixed powder;

[0038] (2) Fill the mixed powder obtained in step (1) into the mold, and then press it into a ring green body. The structure of the mold is as follows: Figure 1-3 As shown; during molding, by applying a radial 4-pole magnetic field on the outer edge of the middle mold, the green body has an outer radial 4-pole orientation, the molding pressure is 12 MPa, the forming magnetic field strength is 8000 Oe, and the obtained green body has a density of 2.85 g / cm 3 ;

[0039] (3) Place the obtained body in an electric kiln, heat up to 1145°C at a rate of 3°C / min, sinter for 2.5 hours, and grind;

[0040] (4) Magnetize and inspect the ground product.

[0041] The results sho...

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Abstract

A method for reducing cracking of external radial multi-pole magnetic rings of dry-pressed strontium ferrite, comprising the following steps: (1) taking prepared strontium ferrite magnetic powder, adding lubricating binder, mixing, and sieving to obtain Mixing powder; (2) Filling the mixed powder obtained in step (1) into a mold, and then pressurizing it into a ring-shaped blank. During molding, a radial 2n-pole magnetic field is applied to the outer edge of the mold to make the blank. Generate an outer radial 2n magnetic pole orientation, where n is a natural number from 1 to 24; (3) sintering, grinding, and cleaning the formed annular blank to obtain a dry-pressed strontium ferrite outer radial multi-pole magnetic ring; (4) It is the finished product after multi-pole magnetization and surface magnetic flux density detection. The invention has the advantages of simple mold structure, stable production, low cost, safety and reliability, high performance of the obtained magnetic ring, high yield, and no cracking problem.

Description

technical field [0001] The invention relates to a method for reducing the cracking of a dry-pressed strontium ferrite external radial multi-pole magnetic ring. Background technique [0002] Since 2009, the scale of the global motor market has continued to expand, and countries have increasingly higher requirements for motor energy efficiency, resulting in a significant increase in the market demand for brushless motors (energy efficiency levels up to IE3 and above), with broad prospects for development. The permanent magnet rotor is a key component of brushless motors, and its market demand has also surged accordingly. Conventional permanent magnet rotors are spliced ​​by multiple pieces of magnetic tiles, which usually have the following disadvantages: 1) Difficulty in assembly; 2) Flux leakage in the splicing gap; 3) Non-sinusoidal distribution of surface magnetic flux, which makes the motor have obvious torque ripple and Cogging effect, high energy consumption and high n...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F41/02C04B35/26C04B35/622H01F1/113
CPCC04B35/2683C04B35/622C04B2235/6562C04B2235/6567H01F1/113H01F41/0266
Inventor 姚锐刘超郑自儒陈晓宇邓雅之
Owner HUNAN AEROSPACE MAGNET & MAGNETO